This invention relates to the art of sewing garments and crafts using support fabrics for interfacing, underlining, and applique. In one aspect, it relates to using such fabrics made from a thermoplastic fabric that has been electrostatically charged. In a specific aspect, it relates to using interfacing made from electrostatically charged thermoplastic fabric wherein the charge imparts cling thereto that keeps the interfacing fabric firmly in place as it is attached to a garment or other crafted object.
Interfacing is an important part of garments and other hand sewn crafts. Interfacing is any fabric that is "sandwiched" between an outer fabric (referred to as "outer layer") and an inner fabric (referred to as "facing layer"). Interfacing is defined as a third layer of fabric lying between the facing (or lining) and the outer layer of a garment. Interfacing is used in garments to provide shape, stiffness, support, and a tailored look in lapels, cuffs, pockets, hems, collars, and around buttonholes for strength. Interfacing may be used in crafts for shape, support, firmness, and to change the fabric properties, such as drape. Underlining fabrics are of the same general structure as interfacing and serve the same function in sewing (e.g. support and shape). They differ basically only in the absence of a third layer. With underlining fabrics, there generally is no facing layer. Thus, the description of "interfacing" applies to "underlining", except as otherwise indicated. Craft applications include quilting and applique, wearable art, fabric jewelry, and baskets to name a few.
The interfacings presently available are made from virtually any fabric including woven fabrics, nonwoven fabrics and webs, and knit fabrics.
Two types of interfacing are presently in use for attaching interfacing to a garment or craft item. One type is usually referred to as a sew-in interfacing wherein, as the name implies, the interfacing is cut in the desired shape and is sewed or stitched to the outer fabric layer, the facing fabric, or both. The principal problem with sew-in interfacing is that the interfacing must be held in place by pins or temporary basting stitches as the interfacing is stitched into place on the base fabric and/or facing fabric. Pinning and basting are inconvenient, time-consuming, and sometimes not very effective.
The second type of interfacing is referred to as fusible interfacing. This type of interfacing comprises a fabric that has applied thereto a heat sensitive bonding agent or adhesive. Fusible interfacing is usually marketed to the user in bulk quantities. The user must cut the interfacing to the desired shape, lay the interfacing on the facing layer and apply heat to the interfacing with an iron to activate the bonding agent. Once the interfacing is bonded to the facing layer, the outer layer of fabric may be sewn to the interfaced facing layer to cover the interfacing and provide the desired end appearance. Fusible interfacing of various weights and thickness are marketed by Freudenberg Nonwovens, Pellon Division of New York, N.Y. This type of interfacing also comprises a paper backing which covers the bonding agent and is peeled off prior to use. U.S. Pat. Nos. 4,007,835; 4,906,507; and 5,603,101 disclose fusible nonwoven thermoplastic interlining fabrics.
The sew-in and fusible interfacings have been used successfully for many years. However, there are undesirable aspects to both types of interfacing. The sew-in interfacing is often difficult to keep in place as it is attached to the facing layer, because it does not have a bonding agent. The two layers of fabrics tend to slide or slip relative to each other during sewing. For best sewing results, the two or three layers should be maintained together in a non-slip composite. Moreover, the sewing or basting steps are tedious and time-consuming. This may result in the interfacing not being in the proper position or orientation in relation to the facing fabric in the final product and may degrade the appearance. The fusible interfacing requires the additional step of heating the interfacing to activate the bonding agent. This may be a time-consuming and expensive step to a mass producer of garments and/or craft items. The bonding agent may also shrink and bubble or harden and crack in time as well as gum-up the iron used to activate the bonding agent. There is therefore a need for an interfacing material that has good fabric properties and that will remain in place as it is sewed without the use of heat sensitive bonding agents.
The present invention relates to the use of a fabric as an interfacing, underlining, and applique material mad e from electrostatically charged fabric. As defined herein, interfacing, underlining and applique fabric means a web made from synthetic fibers. The fabric may be woven, knitted, or nonwoven such as those manufactured using the meltblowing process or the spunbond (spinning) process. Each process is described briefly below. It has been found that the electrostatic charges create an electrostatic cling between the interfacing and the base fabric sufficient to hold the interfacing firmly in place without the need for pinning, basting, or the use of a heat activated bonding agent.
Woven and knitted fabrics are well-known in the art and for purposes of the present invention need no fuirther description. Since the nonwovens are the preferred interfacing fabrics, a brief description of the most important nonwoven processes may be helpful: meltblowing and spunbonded processes.
Meltblowing is a process wherein a molten polymer is extruded through a meltblowing die to form a plurality of side-by-side fibers. Convergent sheets of air are directed onto opposite sides of the fibers as they leave the die. The air draws and attenuates the fibers to microsized diameters (viz. 05-15 microns). The fiber and air stream is directed onto a moving collector surface where the fibers deposit in a random pattern and form a nonwoven fabric or web. The fabric is held together primarily by interfiber entanglement with some fiber sticking while in the molten or semi-molten state. The fibers may be continuous or discontinuous filaments. By varying operating conditions, meltblown fabrics having different basis weights may be produced.
It is well-known in the art of meltblowing to apply an electrostatic charge to the fibers as they are extruded or, alternatively, after the fabric is formed. Electrostatically charged meltblown webs are often referred to as electrets. Electrets were originally developed for gas filtration applications wherein the charges act to attract particulate matter that flows through the web. Since most nonwoven webs are dielectrics, the charge is very persistent and may be sustained for periods of a year or longer. U.S. Pat. Nos. 4,215,682 and 4,904,174 disclose apparatus for producing electrets by the "hot charging" method as well as test data indicating the filtration efficiency of the webs. PCT application PCT/US/93/09630 and the U. S. counterpart U.S. Pat. No. 5,401,446 disclose "cold charging" methods and apparatus for producing electrets.
Spunbonded fabrics are nonwoven fabrics that are produced by extruding a molten polymer through a spinneret that is a metal disc containing numerous minute holes through which the polymer is forced. Continuous filaments are extruded through the spinneret and are blown by low velocity air and deposited on a moving foraminous conveyer. The hot filaments are still sufficiently molten to bond to themselves at their crossover points. The desired orientation of the filaments in the web are achieved by rotating the spinneret, by electrical charges, by controlled airstreams, and by the speed of the conveyer. The web can be additionally bonded by passing through compaction rolls and/or hot-roll calendering. Spunbonded webs generally have larger average diameter filaments (viz. 10-100 microns, typically 20 to 60 microns) than meltblown webs and, therefore, tend to be heavier and stiffer. Spunbonded webs can be electrostatically charged by methods described in U.S. Pat. Nos. 4,592,815; 4,375,718; and 5,401,446.
A paper presented at "Fiber Producer Conference 1983", in Greenville, S.C. entitled "Nonwoven Fabrics: Spunbonded and Meltblown Processes" describes the two processes in detail. The disclosures of this paper are incorporated herein by reference.